Torque screw driver



Feb.s,1946. w, STRRIE, -2,394,022

ToRQuE scREw DRIVER Filed April 7, 1944 Ewa/www ATTORNEYS INVENTOR Patented Feb. 5, 1946 UNITED STATE 'ronduit SCREW DRIVER Mossberg Company, chusetts william sterne, Romford,

R. I., assignorto Apco a corporation of Massa- Applicaton April 7, 1944, Serial No. 529,905

(Cl. 'Z3-13.6)

9 Claims.

This invention relates to a hand tool, more particularly to a tool which is twisted about its longitudinal axis for doing Work at one end thereof such as a screw driver.

In a screw driver or some such tool the handle is usually rigidly connected to the blade of the screw driver so that when the handle is turned about its central longitudinal axis the blade will turn a corresponding amount. At times it is desirable to prevent excessive force from being delivered from the handle to the part which engages the work, which, in the case of a screw driver, is the blade, in order that the work will not be ruptured such as the screw threads stripped by excessive force applied, especially is this true where the tool is in the hands of an unskilled workman.

One of the objects of this invention is to provide a resilient connection between the handle and the work engaging tool shank so that after a predetermined amount of force is exerted the same will yield and will indicate the yamount oi pressure applied that the operator may know by observation the force which is being exerted upon the work.

Another object of this invention is to provide a simple construction which Will be relatively7 -free from friction.

Another object of this inventionv is to provide a pair of resilient members through which force is applied and to so Yarrange these members that they will not friction one upon the` other upon twisting.

With these and other objects in view; the invention consistsA of certain novel features of construction, as will be more fully described and particularly pointed out in the appended claims.

In the accompanying drawing:

t Plig. 1 is a sectional View through the torque oo .I

Fig. 2 is a view similar to Fig., l illustrating a partial turning of the handle with reference to the work engaging member, showing a twisting of the resilient connection between the handle and the member;

Fig. 3 is a section online 3-3 of Fig. l;

Fig. 4 is a diagrammatic detail illustrating means for limiting the rotation of the relatively moving parts;

Fig. 5 is a view similar to Fig. l illustrating a modification.

In proceeding with this invention I provide a member which will engage the work. A screw driver blade is illustrated as the Work engaging means in this showing. I also provide a handle and connect the tool engaging member with the handle through a plurality of ribbon like steel springs which may be twisted. The springs are spaced so that when twisted no friction will occur between them to throw ofi the accuracy oi the tool. These parts are conveniently mounted in a body which serves as a partial housing for them.

With reference to the drawing the body of my tool is designated generally III and consists of a hollow tubular tapered casing II open throughout substantially its length as at I2. At the lower end of this casing II a tool engaging member I3 is secured by being inserted into a bore I4 of the body and provided with a pin I5 which extends through the body and through the member I3. The particular tool here shown is a screw driver provided with a blade I6 so as to enter the slot of a screw for turning the same.

At the upper end of the body the casing II is enlarged as at I1 and receives a ball bearing I8 which rotatably mounts the stern I9 provided-with a flange 20 and a portion the bushing 22 having threaded engagement as at 23 with the enlarged portion I1 of the casing. On the outer portion 24 of this stem a handle 25 is fixedly secured. The bushing is provided with a hexagonal flange 26 to be engaged by a wrench for setting it into the threads 23 for securing it in position.

The lower portion of the stem I9 and the member I3 of the work engaging member are both provided with spaced slots as at 30, 3l .and 32, 33. Resilient are suitably anchored in tend from the stem to the tool engaging member in parallel relation and spaced one from the other. The arrangement is such that when the handle is moved in the ball bearing I8 these strips, by being stiff, transmit this turning movement to the tool engaging member I3 in correspondence with the turning which is imparted to the handle 25 until their inherent resistance to turning is overcome by resistance at the member I3.- When the work offers suiilcient resistance the strips will then twist about an axis between them so as to dispose their upper ends in a different plane from their lower ends as shown at 36 in Fig. 2. Upon release of the handle the strips will regain their parallel plane relation nd will return the handle to initial position.

In order that the amount of twisting may be known and graduated a scale 31 is xedly mounted upon adlange 38 extending outwardly 2| which is guided in f ribbon like steel strips 34 and 35 y these slots so as to exfrom the casing I1.' This scale is graduated in inch pounds as illustrated in Fig. 3. A pointer 39 is xed to the stem which carries the handle 25 and is arranged to move over this scale so that the person who is operating the tool by turning the handle 25-may observe by means of the pointer moving over the scale the amount of pressure or force which is being exerted on the work after resistance is encountered and may set up the screw-with the desired force by accurate measurement rather than depending upon the feel or touch.

In order to limit the relative movement of the movable parts the pointer 39 is. slotted as at 40 (see particularly Fig. 4) and a pin 4| which is fixed relative to the scale by being mounted in the Vcasing I 'l extends into the slot 40 so as to engage either the end 42 or the end 43 of thisA slot upon relative movement of the parts that a limit to the relative movement may be had.

In the case of Fig. 5 instead of using two strips I have provided three strips designated 615, 5,

and 41, and it will be readily/,apparent that any number of a plurality of strips-may be provided.

In each case, however, the strip will be positioned yin spaced relation sc that upon turning of the parts, even through ninety degrees, they will not touch the variable friction to disturb the reading on the scale will not occur. Especially might this be true of the torque governing parts such as resilient strips frictioned one on the other. Y

I claim:

engaging member at one end thereof, a handle in extension ofand mounted on said body for rotative movement about itsy longitudinal axis relative to said member, a plurality of resilient ribbon strips located in said hollow body and connecting said member and handle and through which movement ofthe handle is imparted to said member, said strips being in spaced relation whereby a twisting of the strips through a substantial arc may be had without Contact of one strip with the other.

` 4. In a tool, a hollow body, a longitudinally ex- Y tending work engaging member fixed thereto at l. In a tool, a body, a work engaging member at one end thereof, a handle mounted on said body for rotative movement about its longitudinal axis relative to said member, a plurality of re-` silient ribbon strips connecting said member and handle and through which Ymovement of the handle is imparted tosaid member, said strips being in spaced relation whereby a twisting of the strips through a substantial arc may be had without contact of one strip with the other.

2, In a tool, a body, a work engaging member at one end thereof, a handle mounted on said body for rotative` movement about its longitudinal axis relative to said member, a pair of resilient ribbon strips connectingsaid member and handle and through which movement of the handle is imparted to said member, said strips being in spaced relation whereby a twisting vof the strips 'through 'a substantial arc may be had without contact of one strip with the other.

3. In a tool, a hollow tubular body, a work one end thereof, a handle mounted on the body at the other end thereof for rotation relative to the body, spaced resilient strips extending from the handleto the member through which twisting torque is transmitted from the handle to the member to turn the same about its longiudinal central axis. l

5. In a tool, a hollow body, a longitudinally extending work engaging member fixed thereto at one end thereof, a handle mounted on the body at the other end thereof for rotation relative to the body, spaced resilient strips in said body exe tending from the handle to the member through which twisting torque is transmitted from the handle to the member to turn the same about its longitudinal central axis.

6. In a tool, a body, a longitudinally extending work engaging member lxedthereto at one end thereof, a handle mounted on the body at the other end thereof for rotation relative to the body, spaced resilient strips extending* from the handle to the member through which twisting torque is transmitted from the handle to thev member to turn the same about its longitudinal central axis, a scale carried by the body and a pointer carried by the handle and movable over the scale.

7. A tool substantially as set forth in claim 6 in which the scale is in a plane at right angles to the axis of the body for observance in looking axially of the tool.

8.- A tool substantially as set forth in claim 6 in which the pointer isrprovided with anarcuate slot and a pin fixed relative to the scale and body extends into said slot to limit the relative move- `9. A. tool as set forth in claim l'wherein there is a stop to limit the relative rotationY of lsaid member and handle.,

WILLIAM STORRIE. 

